The answer is A
Explanation: the conservation of matter means that the mass stays the same
"An object weighs about two times as much on Jupiter as on Neptune." Hope this helps :)
A hot air balloon rises in the first place because the air inside is hot, which rises. So, if the air inside is not heated, it fails to rise and falls. Warm air rises because the particles get excited and jiggle with the heat, and cause the air to take up more space. So, as the surrounding air is probably colder and denser, the less dense hot air rises up in the hot air balloon.
I think u would add them all up and then write down your answers